Chain lock

ABSTRACT

A chain lock has two lock parts ( 1 ) which can be displaced in the longitudinal direction of the lock in order to open and close the lock. Each lock part ( 1 ) has a journal ( 5 ) which is arranged on one end and a pocket ( 6 ) which is arranged on the other end. The journal ( 5 ) of one lock part ( 1 ) fits, respectively, into the pocket ( 6 ) of the other lock part ( 1 ). The journals ( 5 ) and the pockets ( 6 ) are both similar in height (H) to the inner width of the lock and each journal ( 5 ) has several retaining frames ( 7, 8 ), associated with several retaining grooves ( 13, 14 ) in the pocket ( 6 ) of the other lock part ( 1 ).

TECHNICAL FIELD

The invention relates to a chain lock for link chains having two lockparts which can be displaced by limited amounts with respect to eachother in the longitudinal direction of the lock in order to open andclose the lock and in each case have two ends which are connected toeach other via a longitudinal web and of which in each case one forms astud having a retaining web extending over part of the circumference ofthe stud and in each case one is provided with a recess serving toreceive the stud and having a retaining groove for the retaining web.

PRIOR ART

A chain lock of the above type is disclosed in DE 199 14 014 C2. In thecase of the known chain lock, the retaining stud is provided, as in thecase of other similar chain locks known, for example, from DE patent 2354 028, with an individual retaining web and an individual retaininggroove assigned to the retaining web, the supporting surface of theretaining web, which supporting surface serves to transmit transverseforces, and the mating surface of the retaining groove, which matingsurface interacts with said supporting surface, being situatedessentially in the longitudinal central plane of the lock. As has beenshown in practice, with increasing static and dynamic loading, theretaining web is the part of the chain lock which is subjected to thegreatest amount of stress. Taking account of this circumstance, it hasbeen proposed in DE 26 38 443 C3 to design the retaining webs andretaining grooves in a beveled manner in order thereby to obtain anincrease of the cross section of the retaining stud. However, anoticeable improvement of the strength cannot be achieved in this mannereven if, following the teaching of DE 77 05 179 U, the connectingpoint—as is conclusive per se—is arranged in a region of the chain linkends, over the cross section of which the local distribution of stressis more balanced. The reason for the success sought failing tomaterialize may be found in the fact that due to the beveled position ofthe retaining web and the retaining groove, the portion of tensileforces which are to be absorbed by that end of the retaining web whichis directed toward the interior of the lock takes on values which leadto the retaining web tearing off in the above mentioned region.

SUMMARY OF THE INVENTION

The invention is based on the object, in the case of a chain lock of thegeneric type under consideration, of obtaining an increase in the staticand dynamic stress by means of an optimized distribution of the forcesand stresses occurring under load in the lock. The object set isachieved according to the invention by the fact that the height of thestud and of the recess is essentially equal to the inner width of thelock, and by the fact that the stud has a plurality of retaining websand the recess has a plurality of retaining grooves.

The multistage design of the studs and recesses and the selection of agreater height of the studs and recesses in comparison to the knownconstructions leads to a balanced and favorable distribution of thestresses and, in particular, of the transverse forces in the couplingregion of the lock parts and, as a result, makes the sought increase instrength possible.

Further features and details of the invention emerge from the subclaimsand the description below of a particularly advantageous embodiment ofthe invention which is illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows the perspective view of one of two identical lock parts,

FIG. 2 shows, partially in section, the side view of the lock partaccording to FIG. 1,

FIG. 3 shows a section along the line III-III in FIG. 2,

FIG. 4 shows the plan view of the lock part according to FIG. 2,

FIG. 5 shows two lock parts in a first position,

FIG. 6 shows the lock parts according to FIG. 5 in a second position,and

FIG. 7 shows the lock parts according to FIG. 5 in their end position.

WAYS OF IMPLEMENTING THE INVENTION

The lock part 1 illustrated in FIGS. 1 to 4 has two ends 3 and 4 whichare connected via a longitudinal limb 2 and of which the end 3 isprovided with a stud 5 and the end 4 is provided with a recess 6 forreceiving the stud 5. The stud 5 is provided with two retaining webs 7and 8 which protrude over their entire length approximately 2 to 6 mmabove the neck-shaped sections 9 and 10 of the stud 5. The height H ofthe stud 5 corresponds essentially to the inner width b_(i) of thefitted chain lock (cf. FIGS. 2 and 7). The use of a stud 5 with just tworetaining webs 7, 8 has proven expedient, especially in the case ofsmaller and medium lock sizes, not least for economic considerations.

The distance a between the retaining webs 7, 8 is larger than the widthb_(s) of the retaining webs 7, 8. Owing to the comparatively largedistance a between the retaining webs 7, 8, there is sufficient spacefor providing a transverse hole 11 for receiving a securing pin (notillustrated in the drawing). Those curved sections of the retaining webs7, 8 which are at the greatest risk of fracturing under load aresituated in regions positioned outside the longitudinal central plane12, i.e. in zones in which the transverse forces acting on the retainingwebs 7, 8 are lower than in the longitudinal central plane.

The recess 6 serving to receive the stud 5 of a second lock part 1 hasretaining grooves 13, 14, the width b_(n) of which correspondsessentially to the width b_(s) of the retaining webs 7, 8, i.e. in thesame manner as the distance a′ between the retaining grooves 13, 14,b_(n) is only a little larger than the width b_(s) or the distance a, sothat, in the fitted state of the chain lock, a virtually play-freeconnection between the studs and the recesses can be assumed. In theregion of the section 15 of the recess 6 a transverse hole 16 isprovided which, in the fitted state of the lock, is aligned with thetransverse hole 11 of a stud 5 introduced into the recess 6.

Both the stud 5 and the recess 6 have a cross section which widenstoward the interior of the lock part 1. As is apparent from FIG. 4, theflanks of the stud 5 and the inner walls of the recess 6 enclose anangle a between them. This angle α is preferably 10 to 30°, but may alsobe smaller. The wedge-shaped design of the stud 5 and the matching shapeof the recess 6 have proven advantageous in this respect because itmakes it much easier to release the lock after a relatively long periodof use and the formation of frictional corrosion which generally resultsfrom this; namely a comparatively light blow of the hammer against oneof the lock parts is sufficient in order to separate them from eachother.

The wedge shape also has a further positive effect which is explainedwith reference to FIGS. 5 and 6. FIG. 5 shows two identical lock partsin a position which they would have to assume during joining together inthe direction of the arrows 17, 18 if the flanks of the studs 5 and theinner walls of the recesses 6 were to run parallel to one another. Bycontrast, the conditions can be seen in FIG. 6 which permit them to bejoined together in the direction of the arrows 17, 18 on account of thewedge-shaped design of the stud 5 and of the recess 6. By means of thewedge-shaped design of the flanks of the stud and of the side walls ofthe recess, the dimension l₁ in FIG. 5 can be increased to a value l₂.This increase considerably facilitates the assembly of the lock inpractice.

1. A chain lock for link chains with two lock parts (1) which can bedisplaced by limited amounts with respect to each other in alongitudinal direction of the lock in order to open and close the lock,each lock part having opposed ends which are connected to each other viaa longitudinal web (2), one of said opposed ends forming a stud (5)having a retaining web (7) extending over part of a circumference of thestud, and the other of said opposed ends being provided with a recess(6) for receiving the stud (5) and having a retaining groove (13) forthe retaining web (7), characterized in that the stud (5) and the recess(6) have a height (H) which is equal to an inner width (b₁) of the lock,and in that the stud (5) has a plurality of said retaining webs (7, 8)arranged one above another, and the recess (6) has a plurality of saidretaining grooves (13, 14) arranged one above another.
 2. The chain lockas claimed in claim 1, characterized in that a distance (a and a′,respectively) between the retaining webs (7, 8) and the retaininggrooves (13, 14) is equal to a width (b_(s) and b_(n), respectively) ofthe retaining webs (7, 8) and the retaining grooves (13, 14).
 3. Thechain lock as claimed in claim 1, characterized in that a distance (aand a′, respectively) between the retaining webs (7, 8) and theretaining grooves (13, 14) is larger than the width (b_(s) and b_(n),respectively) of the retaining webs (7, 8) and the retaining grooves(13, 14).
 4. The chain lock as claimed in claim 1, characterized in thatthe stud (5) has two retaining webs (7, 8) and the recess (6) has tworetaining grooves (13, 14).
 5. The chain lock as claimed in claim 1,characterized in that the stud (5) and the recess (6) are provided witha respective transverse hole (11, 16) serving to receive a securingelement, which can also be used for transmission of force.
 6. The chainlock as claimed in claim 1, characterized in that the stud (5) and therecess (6) have a cross section which widens or expands continuously inthe longitudinal direction of the lock.
 7. The chain lock as claimed inclaim 6, characterized in that the flanks of the retaining webs (7, 8)are wedge-shaped and that side wall sections of the retaining grooves(13, 14) which face the flanks of the retaining webs (7, 8) have a bevelcorresponding to a wedge angle (α) of the flanks of the retaining webs.8. The chain lock as claimed in claim 1, characterized in that flanks ofthe stud (5) and side walls of the recess (6) enclose an angle (α) of 10to 30°.
 9. The chain lock as claimed in claim 1, characterized in thatthe retaining grooves (13, 14) have a depth (t_(n)) of 2 to 6 mm, whichreceive the retaining webs (7, 8) essentially without play.
 10. Thechain lock as claimed in claim 1, characterized in that the retainingwebs (7, 8) have a height which is approximately 2 to 6 mm.
 11. A chainlock for link chains with two lock parts (1) which can be displaced bylimited amounts with respect to each other in a longitudinal directionof the lock in order to open and close the lock, each lock part havingopposed ends which are connected to each other via a longitudinal web(2), one of said opposed ends forming a stud (5) having a retaining web(7) extending over part of a circumference of the stud, and the other ofsaid opposed ends being provided with a recess (6) for receiving thestud (5) and having a retaining groove (13) for the retaining web (7),characterized in that the stud (5) has a plurality of said retainingwebs (7, 8) arranged one above another, and the recess (6) has aplurality of said retaining grooves (13, 14) arranged one above another.12. The chain lock as claimed in claim 2, characterized in that the stud(5) has two retaining webs (7, 8) and the recess (6) has two retaininggrooves (13, 14).
 13. The chain lock as claimed in claim 3,characterized in that the stud (5) has two retaining webs (7, 8) and therecess (6) has two retaining grooves (13, 14).
 14. The chain lock asclaimed in claim 2, characterized in that the stud (5) and the recess(6) are provided with a respective transverse hole (11, 16) serving toreceive a securing element, which can also be used for transmission offorce.
 15. The chain lock as claimed in claim 3, characterized in thatthe stud (5) and the recess (6) are provided with a respectivetransverse hole (11, 16) serving to receive a securing element, whichcan also be used for transmission of force.
 16. The chain lock asclaimed in claim 2, characterized in that the stud (5) and the recess(6) have a cross section which widens or expands continuously in thelongitudinal direction of the lock.
 17. The chain lock as claimed inclaim 11, characterized in that a distance (a and a′, respectively)between the retaining webs (7, 8) and the retaining grooves (13, 14) isequal to the width (b_(s) and b_(n), respectively) of the retaining webs(7, 8) and the retaining grooves (13, 14).
 18. The chain lock as claimedin claim 11, characterized in that a distance (a and a′, respectively)between the retaining webs (7, 8) and the retaining grooves (13, 14) islarger than the width (b_(s) and b_(n), respectively) of the retainingwebs (7, 8) and the retaining grooves (13, 14).
 19. The chain lock asclaimed in claim 11, characterized in that the stud (5) has tworetaining webs (7, 8) and the recess (6) has two retaining grooves (13,14).
 20. The chain lock as claimed in claim 11, characterized in thatthe stud (5) and the recess (6) are provided with a respectivetransverse hole (11, 16) serving to receive a securing element, whichcan also be used for transmission of force.